If a satellite is placed in synchronous orbit above the equator to revolve in the same direction of the earth's rotation and synchronized with the earth's rotation, the satellite will continually remain above a fixed point on the surface of the earth. Many communications satellites have been placed in these synchronous orbits to provide continuous communications capabilities in almost all regions of the globe.
Generally, active communications satellites are orbiting repeaters with broadband characteristics. A signal from a ground station is intercepted by the satellite, converted to another frequency, and retransmitted at a moderate power level to an end user receiver. This provides much better signal strength at the receiving end of the circuit as compared with a signal that is merely reflected from a passive satellite. Active communications satellites are placed in synchronous orbits, making it possible to use them with fixed antennas, a moderate level of transmitter power, and at any time of the day or night. Synchronous satellites are used for television and radio broadcasting, communications, weather forecasting, and military operations.
Further, a constellation of satellite systems such as INMARSAT® is used to cover major regions of the globe to enable ground-to-aircraft (and aircraft-to-ground) communications via the satellite systems. One example of such a constellation is INMARSAT I4, which currently comprises three satellites located in geostationary orbits, each generally covering a region of approximately one-third of the globe with a certain amount of overlap between regions. These satellites are used to provide circuit switched and packet switched data connection as well as additional services, such as Broadband Global Area Network (BGAN) and Swift Broadband (SBB).
INMARSAT®, ViaSat, Intelsat and Eutelsat satellites support various different types of communications services to the aeronautical, maritime and land mobile markets. An airborne satellite communication system can provide an aircraft with multiple digital voice, fax, and real-time Internet communications capabilities. These systems are specifically adapted for use in global two-way, ground-to-air communications by aircraft operators requiring global voice, fax, and Internet communications for their flight crews and passengers.
As the general communications need to transmit more data in larger files at faster speeds grows, so too does the need for faster connections and increased data throughput. This holds true for any communications system, whether strictly ground-based, air-to-ground, or ground-to-air. One way developers of ground-based systems have addressed this need is through the use of acceleration and compression technologies. Acceleration and compression can be achieved through any number of techniques to reduce data traffic volumes such as selective caching, vertical data analysis, adaptive packet compression, packet aggregation and flow control, and so on. This ground-based technology contributes to increasingly faster connection speeds.
The same need for high-speed data connections that currently exist in the office or at home also exist in aircraft cabins. However, ground stations that support global two-way, air-to-ground ATG and ground-to-air GTA communications have not offered equivalent increases in data rates, and especially not in a cost-effective way.
U.S. Pat. No. 7,660,579 titled Communication network acceleration system and method issued Feb. 9, 2010 describes mobile ground-to-air and air-to-ground communication network acceleration that reduced the cost of airborne communication services by creating a faster connection and increasing data throughput. In one embodiment, the communication network acceleration system and method provide as much as a four-fold increase over standard high-speed data rates. This increase is made possible in part through the integration, implementation, and use of acceleration and compression technologies in the ground system that supports communications to and from an airborne terminal.
U.S. Pat. No. 7,761,793 titled SATCOM data compression system and method issued on Jul. 20, 2010 discloses a method of data compression for compressing a web page with graphics files, text files, JAVA scripts, and HTML files comprises storing the graphics files, the text files, the JAVA scripts, and the HTML files in a temporary directory. The graphics files are sorted into lossless and lossy file groups. The files are concatenated and then compressed to yield a compressed web page. Optimal file concatenation size range is determined to optimally develop compression performance while minimizing latency. The concatenated file size is regulated to the optimal file concatenation size.
In business aviation, connectivity is key. With the availability of several Satcom or air-to-ground systems, many business aircraft are being equipped with two or more such systems. With different voice and data communication paths off the aircraft, a confusing array of options is now available for passengers and operators to configure, manage and operate.
Thus, the need exists for solutions to the above problems with the prior art with a Satcom Direct router as a single line-replaceable unit to act as the communications hub for all aircraft links—voice or data.